1971 Dan Armstrong up for sale on Reverb in July 2015 for $3,950 from Southside Guitars in Brooklyn. Seems to be a very clean guitar and likely includes the original pickups, but has a non-original case.
"This Ampeg Dan Armstrong Lucite guitar is all original and in very clean shape. It comes with the humbucker pickup, which is the rarest version, and there is also another single coil pickup in the case. This guitar sounds exceptionally good and plays great. It comes with a non original case."
Back on the market in April 2017, using many of the same pictures as above (plus a few new ones of the case). Reverb has an asking price of $4,500.
Nice Collectors Bundle! This is an all-original, 1971
"Dan Armstrong Guitar! Extremely clean, with no scratches, dents or fret wear! It comes with 3 pickups, an original Sustain Treble humbucker, a reissue Treble Sustain humbucker and a uncertain type of single coil (probably the Rock Treble)..."
"There's so much to learn about these Armstrong guitars, it can be daunting! the serial number on the neck dates it to be late '71 right before these were at the end of their production. Nice, chunky neck with 24 frets.. 24.5" scale.. Cool wiring to create your tones with... Comes with a hard shell case and is setup perfectly and plays great!"